At perihelion on Feb. 9, 1986, Halley’s comet was 8.79 × 107 km from the sun and was
moving at a speed of 54.6 km s−1 relative to the sun. Calculate its speed (a) when the comet
was 1.16 × 108 km from the sun, and (b) at its next aphelion in the year 2024, when the
comet will be 5.28 × 109 km from the sun.